Question

Scavenger cell of connective tissue proper is called as
A. Fibroblast cell
B. Mast cell
C. Mesenchymal cell
D. Macrophage

Answer 1

Hint: Scavenger cell is a cell that can ingest bacteria, foreign particles, and other cells. They are phagocytic cells. Phagocytes ingest and kill microbes, the present antigen to lymphocytes, scavenge degenerating material, and release mediators.

Complete answer:
The scavenger cell of connective tissue proper is called a macrophage. A macrophage is a type of phagocyte, which is a cell responsible for detecting, engulfing, and destroying pathogens and apoptotic cells. Macrophages are produced through the differentiation of monocytes, which turn into macrophages when they leave the blood. Macrophages also play a role in alerting the immune system to the presence of invaders.
-When inflammation occurs, monocytes undergo a series of changes to become macrophages and target cells that need eliminating. Once engulfed, cellular enzymes inside the macrophage destroy the ingested particle. Some macrophages act as scavengers, removing dead or necrotic cells while others provide host immunity by engulfing microbes.
-An ingested microbe or dead cell is engulfed in a phagosome. A phagosome is a vesicle that is formed around the microbe by the cell membrane. This then fuses with a lysosome, another specialized vesicle that contains digestive enzymes for disintegrating the contents of the phagosome. The fused lysosome and phagosome are referred to as phagolysosomes.
Hence, the correct answer is option D.

Note: Most macrophages can live for several months and can kill hundreds of different bacteria before they die. Macrophages provide a non-specific or innate immunity. The macrophage also helps in adaptive immunity. The function of macrophages is to alert the immune system to microbial invasion. After ingesting a microbe, a macrophage presents a protein on its cell surface called an antigen, which signals the presence of the antigen to a corresponding T helper cell.